Search results for: William Shepherd

Items from 1 to 20 out of 48 results

article

Dijets at Tevatron cannot constrain SMEFT four-quark operators

Eduard Keilmann, William Shepherd

Journal of High Energy Physics > 2019 > 2019 > 9 > 1-14

Abstract We explore the sensitivity of Tevatron data to heavy new physics effects in differential dijet production rates using the SMEFT in light of the fact that consistent and conservative constraints from the LHC cannot cover relatively low cutoff scales in the EFT. In contrast to the results quoted by the experimental collaborations and other groups, we find that, once consistency of the perturbation...

article

Jet substructure measurements of interference in non-interfering SMEFT effects

Rafael Aoude, William Shepherd

Journal of High Energy Physics > 2019 > 2019 > 8 > 1-25

Abstract The tails of diboson production at the LHC are sensitive to the interference between Standard Model and higher dimension operators parameterizing the effects of heavy new physics. However, helicity selection rules for the diboson scattering amplitudes set an obstruction to the na¨ıve interference contributions of dimension six operators, causing the total diboson rate correction’s leading...

article

Consistent searches for SMEFT effects in non-resonant dilepton events

Stefan Alte, Matthias König, William Shepherd

Journal of High Energy Physics > 2019 > 2019 > 7 > 1-15

Abstract Employing the framework of the Standard Model Effective Field Theory, we perform a detailed reinterpretation of measurements of the Weinberg angle in dilepton production as a search for new-physics effects. We truncate our signal prediction at order 1/Λ², where Λ denotes the new-physics mass scale, and introduce a theory error to account for unknown contributions of order 1/Λ⁴. Two linear...

article

Matching for FCNC effects in the flavour-symmetric SMEFT

Tobias Hurth, Sophie Renner, William Shepherd

Journal of High Energy Physics > 2019 > 2019 > 6 > 1-26

Abstract We calculate the complete tree and one-loop matching of the dimension-six Standard Model Effective Field Theory (SMEFT) with unbroken U(3)⁵ flavour symmetry to the operators of the Weak Effective Theory (WET) which are responsible for flavour changing neutral current effects among down-type quarks. We also explicitly calculate the effects of SMEFT corrections to input observables on the...

article

Built to last: Interactive effects of perceived overqualification and proactive personality on new employee adjustment

Lauren S. Simon, Talya N. Bauer, Berrin Erdogan, William Shepherd

Personnel Psychology > 72 > 2 > 213 - 240

We integrate relative deprivation and broaden and build theories to develop a process‐based model of perceived overqualification and its relationship with new employee adjustment via “broaden and build” mechanisms (i.e., reciprocal relationships between initial status and change trajectories in work‐related positive affect and perceived job autonomy). Additionally, we examine how new employee proactive...

article

Cuckoo’s eggs in neutron stars: can LIGO hear chirps from the dark sector?

Joachim Kopp, Ranjan Laha, Toby Opferkuch, William Shepherd

Journal of High Energy Physics > 2018 > 2018 > 11 > 1-31

Abstract We explore in detail the possibility that gravitational wave signals from binary inspirals are affected by a new force that couples only to dark matter particles. We discuss the impact of both the new force acting between the binary partners as well as radiation of the force carrier. We identify numerous constraints on any such scenario, ultimately concluding that observable effects on the...

article

Consistent searches for SMEFT effects in non-resonant dijet events

Stefan Alte, Matthias König, William Shepherd

Journal of High Energy Physics > 2018 > 2018 > 1 > 1-24

Abstract We investigate the bounds which can be placed on generic new-physics contributions to dijet production at the LHC using the framework of the Standard Model Effective Field Theory, deriving the first consistently-treated EFT bounds from non-resonant high-energy data. We recast an analysis searching for quark compositeness, equivalent to treating the SM with one higher-dimensional operator...

article

Perturbative unitarity constraints on gauge portals

Sonia El Hedri, William Shepherd, Devin G.E. Walker

Physics of the Dark Universe > 2017 > 18 > C > 127-135

Dark matter that was once in thermal equilibrium with the Standard Model is generally prohibited from obtaining all of its mass from the electroweak phase transition. This implies a new scale of physics and mediator particles to facilitate dark matter annihilation. In this work, we focus on dark matter that annihilates through a generic gauge boson portal. We show how partial wave unitarity places...

article

The Z decay width in the SMEFT: y_t and λ corrections at one loop

Christine Hartmann, William Shepherd, Michael Trott

Journal of High Energy Physics > 2017 > 2017 > 3 > 1-44

Abstract We calculate one loop y_t and λ dependent corrections to Γ ¯ Z , R ¯ f 0 $$ {\overline{\Gamma}}_{\mathrm{Z}},{\overline{R}}_f^0 $$ and the partial Z widths due to dimension six operators in the Standard Model Effective Field Theory (SMEFT), including finite terms. We assume CP symmetry and a U(3)⁵ symmetry in the UV matching onto the dimension six operators, dominantly broken...

chapter

Flapping flexible fish

Robert G. Root, Hayden-William Courtland, William Shepherd, John H. Long

Animal Locomotion > The Hydrodynamics of Swimming > 141-159

In order to analyze and model the body kinematics used by fish in a wide range of swimming behaviors, we developed a technique to separate the periodic whole-body motions that characterize steady swimming from the secular motions that characterize changes in whole-body shape. We applied this harmonic analysis technique to the study of the forward and backward swimming of lamprey. We found that in...

article

Effective interpretations of a diphoton excess

Laure Berthier, James M. Cline, William Shepherd, Michael Trott

Journal of High Energy Physics > 2016 > 2016 > 4 > 1-18

Abstract We discuss some consistency tests that must be passed for a successful explanation of a diphoton excess at larger mass scales, generated by a scalar or pseudoscalar state, possibly of a composite nature, decaying to two photons. Scalar states at mass scales above the electroweak scale decaying significantly into photon final states generically lead to modifications of Standard Model Higgs...

article

Monochromatic gamma rays from dark matter annihilation to leptons

Adam Coogan, Stefano Profumo, William Shepherd

Journal of High Energy Physics > 2015 > 2015 > 8 > 1-17

Abstract We investigate the relation between the annihilation of dark matter (DM) particles into lepton pairs and into 2-body final states including one or two photons. We parametrize the DM interactions with leptons in terms of contact interactions, and calculate the loop-level annihilation into monochromatic gamma rays, specifically computing the ratio of the DM annihilation cross sections into...

article

Dark matter in the coming decade: Complementary paths to discovery and beyond

Daniel Bauer, James Buckley, Matthew Cahill-Rowley, Randel Cotta, more

Physics of the Dark Universe > 2015 > 7-8 > Complete > 16-23

In this report we summarize the many dark matter searches currently being pursued through four complementary approaches: direct detection, indirect detection, collider experiments, and astrophysical probes. The essential features of broad classes of experiments are described, each with their own strengths and weaknesses. The complementarity of the different dark matter searches is discussed qualitatively...

article

Flavour, electroweak symmetry breaking and dark matter: state of the art and future prospects

Giulia Ricciardi, Alexandre Arbey, Enrico Bertuzzo, Adrián Carmona, more

The European Physical Journal Plus > 2015 > 130 > 10 > 1-44

With the discovery of the Higgs boson the Standard Model has become a complete and comprehensive theory, which has been verified with unparalleled precision and in principle might be valid at all scales. However, several reasons remain why we firmly believe that there should be physics beyond the Standard Model. Experiments such as the LHC, new B factories, and earth- and space-based astro-particle...

article

The Heterogeneity of Well‐Being: Implications for HR Management Practices

William Shepherd

Industrial and Organizational Psychology > 7 > 4 > 579 - 583

article

A Review of the Available Urology Skills Training Curricula and Their Validation

William Shepherd, Karan Singh Arora, Hamid Abboudi, Mohammed Shamim Khan, more

Journal of Surgical Education > 2014 > 71 > 3 > 289-296

The transforming field of urological surgery continues to demand development of novel training devices and curricula for its trainees. Contemporary trainees have to balance workplace demands while overcoming the cognitive barriers of acquiring skills in rapidly multiplying and advancing surgical techniques. This article provides a brief review of the process involved in developing a surgical curriculum...

article

Tagging boosted Ws with wavelets

Vikram Rentala, William Shepherd, Tim M. P. Tait

Journal of High Energy Physics > 2014 > 2014 > 8 > 1-14

Abstract We present a new technique for distinguishing the hadronic decays of boosted heavy particles from QCD backgrounds based on wavelet transforms. As an initial exploration, we illustrate the technique in the particular case of hadronic W boson decays, comparing it to the “mass drop” cut currently used by the LHC experiments. We apply wavelet cuts, which make use of complementary information,...

article

Proton decay at M _pl and the scale of SUSY-breaking

Michael Dine, Patrick Draper, William Shepherd

Journal of High Energy Physics > 2014 > 2014 > 2 > 1-11

Abstract It is sometimes argued that a virtue of pushing the supersymmetry breaking scale above 1 PeV is that no particular flavor structure is required in the soft sector in order to evade bounds on flavor-changing neutral currents. However, without flavor structure, suppressing generic Planck-suppressed contributions to proton decay requires even higher SUSY scales, of order 10¹¹ (10⁹) GeV for...

article

Impact of LSP character on Slepton reach at the LHC

Jonathan Eckel, Michael J. Ramsey-Musolf, William Shepherd, Shufang Su

Journal of High Energy Physics > 2014 > 2014 > 11 > 1-22

Abstract Searches for supersymmetry at the Large Hadron Collider (LHC) have significantly constrained the parameter space associated with colored superpartners, whereas the constraints on color-singlet superpartners are considerably less severe. In this study, we investigate the dependence of slepton decay branching fractions on the nature of the lightest supersymmetric particle (LSP). In particular,...

article

The muon anomalous magnetic moment in the reduced minimal 3-3-1 model

Chris Kelso, P. R. D. Pinheiro, Farinaldo S. Queiroz, William Shepherd

The European Physical Journal C > 2014 > 74 > 3 > 1-9

We study the muon anomalous magnetic moment $$(g-2)_{\mu }$$ ( g - 2 ) μ in the context of the reduced minimal 3-3-1 model recently proposed in the literature. In particular, its spectrum contains a doubly charged scalar ( $$H^{\pm \pm }$$ H ± ± ) and gauge boson ( $$U^{\pm \pm }$$ U ± ± ), new singly charged vectors ( $$V^{\pm }$$ V ± ) and a $$Z^{\prime...

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INFONA - science communication portal

Search results for: William Shepherd

Dijets at Tevatron cannot constrain SMEFT four-quark operators

Jet substructure measurements of interference in non-interfering SMEFT effects

Consistent searches for SMEFT effects in non-resonant dilepton events

Matching for FCNC effects in the flavour-symmetric SMEFT

Built to last: Interactive effects of perceived overqualification and proactive personality on new employee adjustment

Cuckoo’s eggs in neutron stars: can LIGO hear chirps from the dark sector?

Consistent searches for SMEFT effects in non-resonant dijet events

Perturbative unitarity constraints on gauge portals

The Z decay width in the SMEFT: y_t and λ corrections at one loop

Flapping flexible fish

Effective interpretations of a diphoton excess

Monochromatic gamma rays from dark matter annihilation to leptons

Dark matter in the coming decade: Complementary paths to discovery and beyond

Flavour, electroweak symmetry breaking and dark matter: state of the art and future prospects

The Heterogeneity of Well‐Being: Implications for HR Management Practices

A Review of the Available Urology Skills Training Curricula and Their Validation

Tagging boosted Ws with wavelets

Proton decay at M _pl and the scale of SUSY-breaking

Impact of LSP character on Slepton reach at the LHC

The muon anomalous magnetic moment in the reduced minimal 3-3-1 model

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